3D objects
Faces, edges and vertices of prisms and pyramids, and flat and curved surfaces. Read one part at a time and tap “I know this”. Then test yourself in the quiz.
Know it already? Jump straight to the quiz
3D objects
A face is a flat side; an edge is where two faces meet; a vertex is a corner where edges meet.
| Object | Faces | Vertices | Edges |
|---|---|---|---|
| cube | 6 | 8 | 12 |
| rectangular prism | 6 | 8 | 12 |
| triangular prism | 5 | 6 | 9 |
| square pyramid | 5 | 5 | 8 |
| triangular pyramid | 4 | 4 | 6 |
| pentagonal prism | 7 | 10 | 15 |
| hexagonal prism | 8 | 12 | 18 |
- A prism has two identical, parallel end faces (bases) joined by rectangles. It is named after its base: triangular prism, rectangular prism.
- A pyramid has one base and triangular faces that meet at one point (the apex). It is also named after its base: square pyramid.
Flat and curved surfaces
| Object | Shape of the faces |
|---|---|
| cube | 6 squares |
| rectangular prism | 6 rectangles |
| triangular prism | 2 triangles and 3 rectangles |
| square pyramid | 1 square and 4 triangles |
| cylinder | 2 flat circles and 1 curved surface |
| cone | 1 flat circle, 1 curved surface and a point |
| sphere (ball) | only 1 curved surface, no flat faces |
An object with a curved surface can roll; flat faces let it slide. A cylinder can do both.
Nets
A net is a flat shape that you can fold to make a 3D object. Cube: 6 squares. Triangular prism: 2 triangles and 3 rectangles. Square pyramid: 1 square and 4 triangles. Tetrahedron (triangular pyramid): 4 triangles.
Remember this and test yourself
- Face = flat side; edge = line; vertex = corner.
- Cube: 6 faces, 8 vertices, 12 edges.
- Prism: two identical end faces, joined by rectangles.
- Pyramid: one base and triangles that meet at a point.
- Cylinder: 2 flat circles and 1 curved surface; sphere: only 1 curved surface.
Write these points in your book. Read them again the night before the test.
Cube 6-8-12: faces, vertices, edges.
Important words
First say the answer yourself, then turn the card over.
Match column A to column B
Tap a word in column A, then its meaning in column B. You can also start in column B.
Now the real quiz!
The quiz has many more questions on this topic. Every question shows straight away whether you are right and explains why.
Take the quiz: 3D objects- Let your child work the examples on paper and explain them to you.
- The ticks (“I know this”) are saved on this device only. We never ask for names or emails.
Follows CAPS for Grade 7 Mathematics. Always check your teacher’s notes and textbook too.